Fuel cell assemblies convert a fuel and an oxidant to electricity. One type of fuel cell assembly employs a proton exchange membrane (hereinafter “PEM”) to facilitate catalytic reaction of fuels (such as hydrogen) and oxidants (such as air or oxygen) to generate electricity. The PEM is a solid polymer electrolyte membrane that facilitates transfer of protons from an anode to a cathode in each individual fuel cell normally deployed in the fuel cell assembly.
In a typical fuel cell assembly, individual fuel cell plates include channels through which various reactants, cooling fluids, and byproduct water formed by the reactants during operation of the assembly flow. When the fuel cell assembly is warmer than the ambient environment, water vapor in the fuel cell assembly may condense. In subzero ambient temperatures, the condensate may form ice in the fuel cell assembly. The presence of condensate and ice may affect the performance of the fuel cell assembly.
During operation of the fuel cell assembly, waste heat from the fuel cell reaction heats the assembly and militates against vapor condensation and ice formation in the assembly. However, condensate may flow through the system and accumulate in conduits throughout the fuel cell system, such as a conduit in fluid communication with a pressure sensor in the fuel cell system. Condensate blocking a fluid communication conduit to the pressure sensor may cause false pressure readings by the sensor resulting in a low reactant pressure within the fuel cell. Low reactant pressures can lead to an insufficient supply of the reactants needed to produce a required electrical output. Alternatively, false pressure readings by the sensors can result in a high reactant pressure. Pressure sensors are also susceptible to false readings when the fuel cell is operating at a subzero temperature. Frozen condensate can cause the false readings when the frozen condensate blocks communication between a reactant flow path and the sensor.
It would be desirable to develop a fuel cell system that militates against the accumulation of condensation or ice in a conduit in fluid communication with a pressure sensor, without affecting the pressure or stoichiometry of reactants flowing through a fuel cell stack of the fuel cell system.